CVE-2026-56384: Craft CMS: Authenticated "assets/preview-thumb" discloses signed fallback transform preview link to CP users without asset-view permission

medium Affects craftcms/cms. Feed 2026.10.29.1, updated 2026-10-28; published 2026-07-06; advisory modified 2026-08-06.

Craft CMS: Authenticated "assets/preview-thumb" discloses signed fallback transform preview link to CP users without asset-view permission

Package: craftcms/cms Composer
Affected versions: >=4.0.0-RC1 and <4.17.8 or >=5.0.0-RC1 and <5.9.14
Fixed in: 4.17.8, 5.9.14
Severity: medium
Exploitation: not on CISA KEV · EPSS 0% (26.2th percentile)
Published: 2026-07-06
Source: osv.dev

References

CWE-200 CWE-862

NVD record craftcms/cms advisories

Am I affected?

Find out in one command. phpwarden checks your composer.lock against this advisory and 20,000+ others, ranked by real-world exploitation (CISA KEV + EPSS). Free, offline, open data.

# one-time install
pip install phpwarden

# then
phpwarden deps composer.lock

Or keep it checked automatically: GitHub Action · pre-commit hook · GitLab CI · Laravel artisan command

Install docs How findings are ranked

Related advisories

CVE-2025-32432 KEV critical Craft CMS Allows Remote Code Execution same package: craftcms/cms
CVE-2024-56145 KEV critical Craft CMS has potential RCE when PHP `register_argc_argv` config setting is enabled same package: craftcms/cms
CVE-2025-23209 KEV high Craft CMS has a potential RCE with a compromised security key same package: craftcms/cms
CVE-2025-35939 KEV medium Craft CMS stores arbitrary content provided by unauthenticated users in session files same package: craftcms/cms
CVE-2023-41892 critical Craft CMS Remote Code Execution vulnerability same package: craftcms/cms
CVE-2024-37843 critical Craft CMS SQL injection vulnerability via the GraphQL API endpoint same package: craftcms/cms